The criteria for holding a person (D) responsible in criminal law for a particular harm emerge from moral decisions. These criteria are manifest as statutory laws and as judicially created common laws. For example, D's acts must be voluntary. They must cause the relevant harm. There must be no circumstance of justification or excuse.
The recent Supreme Court of Canada case Maybin v R, 2010 SCC 24 noted here, highlighted the moral basis for attribution of a sufficient causal connection between D's acts and the harm. The Privy Council has recently referred to the moral dimension of diminished responsibility: Daniel v The State (Trinidad and Tobago) [2012] UKPC 15 at [37]-[38].
Parliament tends to limit defences and to create new offences. It seems to be engaged in extending the scope of acts for which a person can be held criminally responsible. Whether that legislative activity really reflects community perceptions of what is right can be a controversial question. But the important point is that if the courts are perceived by Parliament to be going wrong, legislation can correct that error. Whatever the common law might say, it is trumped by legislation. This is why courts should not be shy about developing the common law.
The recent Supreme Court of Canada case Maybin v R, 2010 SCC 24 noted here, highlighted the moral basis for attribution of a sufficient causal connection between D's acts and the harm. The Privy Council has recently referred to the moral dimension of diminished responsibility: Daniel v The State (Trinidad and Tobago) [2012] UKPC 15 at [37]-[38].
The moral dimension is often recognisable by a requirement for reasonableness. Self-defence justifies killing, or any other form of violence, where it is reasonable for D to cause the harm in the circumstances as he believed them to be. This almost universal formulation of self-defence reflects its common law origins. The common law reflects the customs of the people. Reasonable conduct should be lawful because it is perceived as right.
Is the common law merely residual, ever-diminishing as statute advances? Or is the common law a potentially powerful source of justice? It might seem from the High Court of Australia decision in PGA v The Queen, discussed here recently, that the common law perpetually withers, although that would - or should - be a misconception. Judges deal with the requirements of justice in particular cases, and with each case there is potential for development of the common law. This should be as true for defences as it is for any other developments that justice requires. By "justice" I mean here the judicially perceived sense of what the community regards as right. For recognition of this ability to develop new defences, see R v Kingston[1994] 3 WLR 519, at 536 (although in R v Cargill [1995] 3 NZLR 263, (1995) 13 CRNZ 291(CA) I was unable to persuade the Court to recognise a new defence of reasonable demand in relation to a charge of blackmail; that development was subsequently made by legislation: Crimes Act 1961, s 237(2)).
Parliament tends to limit defences and to create new offences. It seems to be engaged in extending the scope of acts for which a person can be held criminally responsible. Whether that legislative activity really reflects community perceptions of what is right can be a controversial question. But the important point is that if the courts are perceived by Parliament to be going wrong, legislation can correct that error. Whatever the common law might say, it is trumped by legislation. This is why courts should not be shy about developing the common law.
Daniel, above, prompts us to think about whether a defence of diminished responsibility should be developed at common law where legislation is silent on that. A defence of insanity will not cover all the states of mind that should negate criminal responsibility. The varieties of what in a loose sense may be called mental disorder seem extensive, as anyone who has glanced at the Diagnostic and Statistical Manual (4th ed) can see. Some of them, as Daniel illustrates, are states of mind that, if established at trial, should lead to acquittal. A court should be allowed to decide whether in a particular case mental abnormality should attract liability. This is what the court in Norway is currently doing, but under the guise of deciding the question of sanity.
An overview of judicial response to mental deficiencies in the context of the (now, former) statutory partial defence of provocation in New Zealand illustrates how moves from absolute rejection to accommodation can be made. In R v McGregor [1961] NZLR 1069 (CA) the Court declined to extend the meaning of provocation in the absence of statutory authority. Some withdrawal from this absolute position is evident in R v McCarthy [1992] 2 NZLR 550, (1992) 8 CRNZ 58 (CA). A variety of mental weaknesses have been accepted as relevant to whether D had in a non-culpable sense lost his self-control: R v Taaka [1982] 2 NZLR 198 (CA) obsessive compulsive personality, R v Pita (1989) 4 CRNZ 660 (CA) aversion to violence, R v Foreman 18/2/92, CA254/91 active schizophrenic process, R v Oakes [1995] 2 NZLR 673 (CA) battered woman's syndrome, R v Timoti [2005] 1 NZLR 466, (2004) 21 CRNZ 90 (CA) paranoid personality disorder.
Does abolition of provocation as a partial defence to murder mean that none of these factors can have any relevance to the attribution of criminal responsibility generally? I think not. But even on a narrow view that they could only be relevant to whether intention or recklessness, or voluntariness, or causation had been proved, there is sufficient flexibility in the mysteries of fact-finding for morality to have an influence.